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PotatoFi

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2 minutes ago, PotatoFi said:

I have to wait a few days for capacitors to arrive anyway, so I might bring it into the house where it is about 72 F and give them some more time. What's interesting is that it's more white where I scrubbed things off using baking soda, probably due to the slight abrasive nature of the baking soda.

Yep, taking the grime and oxidation off with baking soda gave it easier access to the chromophores in the plastic, so it could attack them more easily to reduce the color

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Okay, I played with the hairdryer. No effect. Switched to the heat gun, and that got the plastic moldable. Here's what it looked like before:

IMG_0167.thumb.JPG.4b5f14ff317bfc8ffae21f0a7079e926.JPG

Here's what it looks like now:

IMG_20190325_183705.thumb.jpg.088b43d491c25fb3f956503da9346434.jpgIMG_20190325_183742.thumb.jpg.c9e91e49cd476e66d890950a9fc86507.jpgIMG_20190325_183754.thumb.jpg.d25dbead8d4e96348b676c2f7ae35c8d.jpg

 

I don't know if I made it better or worse. There is a bit of a burn mark on the front now, despite my best efforts to not get things too hot. The problem is that the sunken/burned parts are in the very corners of the plastic where I can't get heat in there and really push on it.

 

So I'm kinda wondering if I need to get some bondo, trim away the parts that stick out too much, and fill the parts that are depressed. Of course I'll never be able to match texture but I can at least fill in some stuff. 

 

I'm 100 percent open to suggestions here. I'm especially keen on saving the front panel because it's an M001 panel. What a shame that the top got burned.

 

Edit: The 8-Bit Guy did an interesting repair on an Apple II with resin... but it was a hole cut in the top. This is on the edge, so I don't think resin will work. I think my best shot is to possibly use body filler and paint a small section of the case. It will never, ever look perfect, but I figure if I can mask it some, that would be good. Looking for opinions about this for sure... I'm just not sure what to do about it.

Edited by PotatoFi

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I still wonder what caused a burn\melt like that on it from the start? I can't think of any items that could do that short of a soldering iron or something like that. It seems too big for a cigarette of any kind. Maybe acid? Was it from an area where chemistry was done?

Edited by Paralel

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I'm not sure of the details, but I do know that it spent a good part of it's life in an aircraft hangar. My guess is a hot torch was set on it. It REALLY burned it. Huge bummer that it got both the front and back cases.

 

I suppose I should consider replacing the case. I must admit that I do like the Platinum cases better than Beige, and my keyboard is Platinum. I don't know what a Macintosh Plus case is worth.

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2 hours ago, Johnnya101 said:

Desk lamp too close is my guess.

That would be one desk lamp I would be afraid to get near...

 

If you plan to keep it. I'd go for a new case. If you plan to pass it alone, I'd go for a zero sum game with it. Do the best you can, get it working, and just let it go for what its worth.

Edited by Paralel

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5 hours ago, PotatoFi said:

I have to wait a few days for capacitors to arrive anyway, so I might bring it into the house where it is about 70 F and give them some more time. What's interesting is that it's more white where I scrubbed things off using baking soda, probably due to the slight abrasive nature of the baking soda.

 

I'm curious, what reference do you have for the 72 F/22 C thing? Personal experience is completely valid here.

72 F/ 22 C in chemistry is considered part of what is known as STP for chemical reactions. STP stands for Standard Temperature & atmospheric Pressure. Standard temperature is room temperature, which is defined as 72 F / 22 C, according to chemistry standards. Standard pressure is considered 1 atm, which is what the atmospheric pressure is on a neutral day (Sunny, Blue Sky, Fluffy white clouds) at sea level, which by chemistry standards is considered standard earth atmosphere. Practically every chemical reaction is done at STP (unless the reaction calls for a different set of conditions), so the standard rule for a chemical reaction is a "standard" room temperature of 72 F/ 22 C. So I just picked that as it is the so called "golden standard" for chemical reactions. Essentially any chemical reaction that is meant to be done without special conditions should work well under STP, as a standard assumption.

Edited by Paralel

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Fantastic explanation @Paralel! Thank you!

 

Okay, I have received my capacitors and have them installed. The very last step is to install the anode cap, but... while the metal parts inside the cap seem to be holding tight, I can't get the suction cup to REALLY suction down. It un-sucks after about 60 seconds. Is this a problem?

 

I'm seriously ready to flip the power switch on it, other than this problem.

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At the risk of sounding stupid, but with the possibility of learning something new, I'll say that I didn't know it was supposed to suction anything, I thought it was just a big insulator so you couldn't accidentally touch the anode with anything, even a small wire.

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No Jinnai, you're correct. Well, really the cap is there because without it the anode wire itself would be arcing everywhere. You NEED the cap to stay "glued" down. That's what the red you usually see in that area is. Glue. You also don't want any nicks damaging the cap. So it sounds like you should reglue the cap somehow. Or, like one of my junk SEs had, duck tape it.

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Yep, despite appearing to be a so-called "Suction Cup" it really isn't able to perform that function on its own, as a true suction cup would.

 

I second Johnny, duct tape works well. Electrical tape also does the job.

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37 minutes ago, LaPorta said:

It would be great if we could find out what the OEM sticky solution was.

Wish I had access to a better lab, I could tell you. I could solubalize it and do an HPLC-MS. Guarantee it would tell me for sure. 

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This is the same as the OEM floppy drive lube...everyone is guessing, but its impossible to find documents as to what it really was.

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1 hour ago, LaPorta said:

Different spikes for different groups...I remember organic chem!

Bingo

 

59 minutes ago, LaPorta said:

This is the same as the OEM floppy drive lube...everyone is guessing, but its impossible to find documents as to what it really was.

Same situation. There are at least 3-4 things in the vintage mac community I could solve with a decent lab. One of these days it will happen.

Edited by Paralel

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Ok, here's what the case and CRT look like today, all nice and restored other than the burn mark. The lighting makes it look a lot more yellow than it really is. It's a very pleasant beige now. The full submersion retrobright seems to have brightened it up just a little bit, which is exactly what I wanted.

 

IMG_20190327_194926.thumb.jpg.6ac5be8972e6fa9888b536fc30fc03c2.jpg

 

I didn't replace all of the caps on the analog board, but I did replace all of the ones on this upgrade list. I had about $15 left in my "geek budget" for the month so I decided to just replace these specifically at first.

 

Here's my tape job on the anode cap. I still don't feel like the metal clip is holding on very tight. :( I put down a square of tape first (not touching the hole in any way), and then another layer of tape holding the cap down:

 

IMG_20190328_102414.thumb.jpg.5dcdfff0ab65adf8c77def212badd6ae.jpg

 

Then I put the case back on, flipped the switch aaaaaaaaaaand... Black screen, no bong, and a low "whooooorrrrrrrrrrrr" buzzing sound. It's not high pitched like a mosquito, it's very low. I quickly turned the switch back off. After a few minutes, I was brave enough to try again, and this time it went "whhhhoooooooorrrr, whhhoooooor, whooor, whor whorwhor" and I shut it down because I was terrified.

 

Anyone want to guess about what is going on? I'm suspecting that the anode clips aren't making good contact, but that is just a guess.

Edited by PotatoFi

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Adding another post as I can't edit anymore... but the fact that there's no chime like there was before is disconcerting. 

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That I haven't heard before. Was anything else moved/disturbed while doing all of this? Anything mistakenly not reconnected?

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19 minutes ago, LaPorta said:

That I haven't heard before. Was anything else moved/disturbed while doing all of this? Anything mistakenly not reconnected?

Nope, everything is properly connected. With the exception of the anode cap, which I messed with and messed with but never really felt was firmly attached. I wonder if that sound is the computer attempting to bong, but there being some crazy under/over volt issue due to the anode cap not being fully connected?

 

Sucks... I REALLY didn’t want to touch the anode cap again!

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Well, don't be so afraid of it :) it won't leap out of it's case to get you, at least. If I were you I would attempt to power it on with the rear case off and figure out if the noise was the speaker, the FDD, or the CRT. I had one that somehow had a short in the CRT, and it made a noise (though not necessarily like this one) and the end glowed purple.

 

I know you said everything is connected but to mention again the ground wire going to a top CRT screw...

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2 hours ago, Jinnai said:

I know you said everything is connected but to mention again the ground wire going to a top CRT screw...

Double-checked and yes, the CRT ground is properly connected.

 

I did another test with the case off. If I turn the power off and back on rapidly, it will chime (hooray)! but then goes into that rapid on-off-on-off thing that you heard. I hear the CRT sounding like it's turning off and back in very rapidly. The sound you hear in the video is not the disk drive.

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I checked the voltage at the floppy connector. +12v is DEAD, the +5v pin is anywhere from ~2.5v to ~4.5v but it jumps around all over the place and is very hard to read.

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